0
$\begingroup$

Heyo! I'll do my best to ask this question as clear as possible, but since English is not my mother tongue it might be hard :D Assignment

I added the assignment above. S is the point of rotation and the arrows are all the forces that make it rotate. I have to put them all in order from the one with the lowest momentum first to the one with the highest momentum. I got to the point where I could say F5 was first, because that one doesn't have any momentum. But I could't get any further. What do i need to do / calculate in order to be able to do this assignment?

Improve this question
$\endgroup$

1 Answer 1

Reset to default
0
$\begingroup$

Do you want the tendency of each force to rotate about Point S? If so, you are correct that F5 has no moment about Point S since it lies on the line of action. Does the problem specify if all the forces are equal in magnitude? The diagram makes it look like they are, and since Moment = ( Lever Arm ) ( Force ), all you have to look at is the lever arm since the force is constant.

F1 = 3 blocks away from S, F2 = 2 blocks away from S, F3 = 2 blocks away from S, F4 = (extrapolate to come up with more blocks and use Pythagorean theorem), F5 = on line of action so 0.

Does this answer your question? If not, or if I made a mistake, I am more than happy to fix it.

Improve this answer
$\endgroup$
4
  • $\begingroup$ Hmmm, but if F2 and F3 are both 2 blocks away, how do I know which has a bigger momentum? Also, what does Extrapolate mean? $\endgroup$
    – Mark Fijn
    Commented Jan 9, 2018 at 19:20
  • $\begingroup$ If the force is the same, and the lever arm is the same as is the case in F2 and F3, the moment will be the same too. Moment is NOT momentum, though. Do you want momentum or tendency to rotate (moment/torque)? Extrapolate means just draw more boxes of the same dimensions. $\endgroup$
    – ProgrammingEnthusiast
    Commented Jan 9, 2018 at 19:23
  • $\begingroup$ Moment, I thought they were the same, my fault :D $\endgroup$
    – Mark Fijn
    Commented Jan 9, 2018 at 19:26
  • $\begingroup$ Momentum is mass times velocity, moment is lever arm times force. Do you have any more questions related to this? Remember to accept the answer! $\endgroup$
    – ProgrammingEnthusiast
    Commented Jan 9, 2018 at 19:28

Not the answer you're looking for? Browse other questions tagged or ask your own question.